Current methods to isolate individual cells from formalin-fixed paraffin-embedded (FFPE) tissue samples lack out-of-plane (z-axis) resolution. These techniques typically utilize laser capture microdissection (LCM) to detach cells glued to a plastic film or a glass plate (x-y plane) either by heat through use of a pulsed infrared laser (see e.g., the PixCell II infrared LCM system commercialized by Arcturus Engineering of Mountain View, Calif., US), or by force against gravity using ultraviolet laser capture microdissection (see e.g., the Palm Zeiss ultraviolet LCM system commercialized by P.A.L.M. Microlaser Technologies AG of Bernried, Germany). Each of these systems are dry systems where the laser energy impinges upon the tissue sample to ablate cells and cell material. The recovery rate of ablated cells is very low and the direct impingement of the laser on the tissue may potentially damage the cells and chemical/structural constituents thereof, thereby negatively impacting study analysis and results. Also, these LCM techniques require the use of an Eppendorf micro-centrifuge-tube which greatly restricts throughput. Moreover these techniques are restricted to two-dimensional (2-D) analysis and cannot be used with samples having layers of cells in the z axis. In other words, traditional LCM approaches are restricted to the x-y plane and lack out-of-plane resolution in the z axis.
One attempt to address the above shortcomings of traditional LCM techniques is to couple a microfluidic device with the laser source. The microfluidic device holds the tissue sample within a chamber and a fluid flows through the chamber where the laser directly impinges upon the tissue sample. One or more cells may be ablated from the tissue sample upon laser impingement. The ablated cells are then received in and carried by the fluid flow to a sample collecting element. Cells may be serially ablated and collected in respective collecting elements. Each respective collecting element may be used to maintain spatial information regarding the collected cells. In this manner, the tissue sample may be interrogated across the x-y plane in a first instance. The laser can then be used to ablate the next successive layer in similar fashion. All of the above cell samples may then be analyzed and any data collected may be correlated to locate the spatial location of the respective cell sample within the entire original tissue sample. However, while achieving resolution in the z-axis with improved sampling efficiencies, direct laser impingement upon the tissue sample may cause damage to the ablated cells or the underlying cell layer of the tissue sample thus negatively impacting any information collected or reported study results.
Accordingly, what is needed in the art is a device and method for isolating, dissecting, collecting, sorting and analyzing individual cells or groups of cells without direct laser impingement upon the tissue sample, as well as the conservation of spatial and morphological information of individual cells or cell groups to enable visualization, recordation and study through multimodal molecular analysis of quantum dissected qubits of tissue voxels.